397
Views
20
CrossRef citations to date
0
Altmetric
Original Articles

Numerical Modeling of Soot Emissions in Diesel Sprays Based on Detailed Fuel and PAH Chemistry

, &
Pages 1696-1714 | Received 08 Mar 2013, Accepted 30 Jul 2013, Published online: 07 Oct 2013
 

Abstract

Numerical modeling of soot formation and oxidation in diesel sprays was conducted using a multistep soot model coupled with reaction mechanisms for fuel oxidation and polyaromatic hydrocarbon (PAH) formation. As new combustion strategies such as low-temperature combustion emerge, the demand for accurate numerical models has also increased to predict the effects of subtle changes in the operating conditions on combustion and exhaust emissions. Accurate prediction of soot emissions from diesel engines remains challenging, particularly for low-temperature combustion conditions with massive exhaust gas recirculation. Soot emissions from the engine are highly sensitive to local temperature and chemical compositions. In this article, an n-heptane mechanism is combined with a detailed PAH mechanism to simulate diesel spray combustion and emissions formation. The mechanisms are validated against experimental data of ignition delays and flame speeds. The overall reaction mechanism consists of 68 species and 145 reactions and is used with a multistep soot model. The multistep soot model is employed to simulate the evolution of soot including inception, surface growth, coagulation, and oxidation. The soot model is validated against experimental results obtained from a constant-volume combustion chamber and a heavy-duty diesel engine. Predicted flame liftoff locations and flame structures agree well with the experimental data. The model was able to predict the characteristics and trends of soot emissions with respect to the level of exhaust gas recirculation. Further analyses of the engine simulation results were conducted for understanding the soot emission characteristics in the engine.

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.